Solid oxide fuel cells utilizing dimethyl ether fuel

The feasibility and benefits of using an oxygenated fuel for solid oxide fuel cell (SOFC) operation were explored using dimethyl ether (DME). A model for the flow tube chemistry was used to predict DME gas-phase decomposition kinetics and species concentration profiles for temperatures ranging from 550 to 750degreesC. The predictions, which were in good agreement with mass spectral measurements, showed that in the absence of a fuel cell DME decomposed primarily into equal amounts of H-2,CH4, and CO above about 675degreesC. The same decomposition species were observed in catalytic reaction experiments at Ni-based anodes, but the mole fractions of the decomposition gases were much higher, between 550 and 650degreesC. Current-voltage measurements were made using SOFCs with 100 mum thick yttria-stabilized zirconia electrolyte supports, (La, Sr)(Co, Fe)O-3 cathodes, and 50 vol % Ni-based anodes. Maximum power densities for SOFCs supplied directly with DME fuel were 0.10 and 0.21 W/cm(2) at 600 and 700degrees C, respectively. No carbon deposition was observed in cells operated at temperatures up to 700degrees C. (C) 2002 The Electrochemical Society.